1. Field of the Invention
The present invention relates to a motor and a method of manufacturing the motor.
2. Description of the Related Art
In a known motor, an insulator made of a resin is attached to each tooth of a stator and a conducting wire is wound around the insulator to define a coil. The insulator is arranged to intervene between the tooth and the coil to provide electrical insulation therebetween. A known motor including such an insulator is described, for example, in JP-A 2005-012861.
During driving of the motor, heat is generated in each coil because of a drive current. It is desirable that the heat generated in the coil should be transmitted out of the motor through, for example, the insulator and the tooth. However, there are a great number of minute gaps between the tooth and the coil, and these gaps constitute a factor in preventing the heat from being effectively transferred from the coil to the tooth. When transmission of the heat from the coil is insufficient, the motor may easily become overheated.
Concerning this point, JP-A 2005-012861 describes a technique of defining a plurality of holes in the insulator and injecting a resin into each hole (see paragraph [0020] of JP-A 2005-012861). The technique of JP-A 2005-012861 enables heat to be transferred from a stator winding to a magnetic pole tooth through the resin arranged in each hole (see paragraph [0021] of JP-A 2005-012861).
However, according to the technique of JP-A 2005-012861, the resin is injected individually into each of the holes defined in the insulator. Therefore, the resins injected into the individual holes are unconnected with each other. Therefore, according to a structure of JP-A 2005-012861, there are only a limited number of paths along which the heat is transferred from the coil to the tooth, and it is thus difficult to further improve heat dissipation efficiency of the motor.
In There has been an increasing demand for small-sized and high-power motors in recent years. Accordingly, there is a demand for a structure that enables heat to be emitted out of a motor more efficiently than in the past.